比如可以这样写代码，CardView就变成普通的FrameLayout：

<?xml version="1.0" encoding="utf-8"?>

<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://schemas.android.com/apk/res-auto"

    xmlns:card_view="http://schemas.android.com/apk/res-auto"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:background="?attr/selectableItemBackground"

    app:cardCornerRadius="0dp"

    app:cardElevation="0dp"

    app:cardPreventCornerOverlap="true"

    app:cardUseCompatPadding="true"

    card_view:contentPadding="0dp">

</android.support.v7.widget.CardView>